Intermittent driving mechanism



D. F. GRAHAME 1,787,265

INTERMITTENT DRIVING MECHANISM Dec. 30, 1930.

Filed Oct. 11 1924 2 SheetS -Sheec 2 lNVENTOR DALLAS F. GRflH/IME WITNESS Y @4 ATTO EY 5cthe illustration;- I

Patented Dec. 30, 1930 f mm s'rj res A NT @FFI'E g pair-Les r. GRAHAME, ori aonrannn, QUEBEC; cannon, assrsnon 'ro snnronn RILEY sroxna CORPORATION, or Wononsrna, MAssAcHUsnTrs, A conrone'rron or MAS- sAoHUsET'rs inTnnMr-Trmvr DRIVING MECHANISM This invention relatesto driving mechanisms and more particularlytoa mechanism capable of rotating a. shaft intermittently through variable periods of time. V In, the operation ofa stoke r, it is desirable to feed coal into the combustion chamber at difierent rates depending upon the load be ing carried and the condition of the fire. It has been customary to utilize a rotary valve for the purpose of admitting steam to the engine which actuates the coal feeding ram, but such rotary valves have involved a con siderable loss of steam dueto leakage and have not bee-n generally satisfactory.

l5 'Ihave found that a poppet type of valve is more satisfactoryfor usewith the steam cylinder of a stoker ram driving engine,

hence one object of'my invention is to provide a mechanism capable of lifting the popzu pet valves automatically and at variable intervals to admit steam tothe cylinder.

The stoker ram may also be suitably driven by other types of driving mechanism such as a reversing electric motor, and it is iifi accordingly a further objectofmy invention to provide a mechanism which maybe .employed to rotate anysuitable controlling device, such as an electric switch of desired construction, whichwill cause the reciproso cation of the ram as desired.

A further object of my invention is to provide a manually controlled automatically operated mechanism of general utility which Iwill rotate a shaft at a uniform rate either continuously or intermittently through vaa is controlling a steam cylinder: I

Fig. 1 is a vertical tront'elevation, partly in section, showing one. arrangement or" a cam-controlled poppet valve actuating mechanism, certain parts being removed to clarify Fig. 2 isaside elevation, partly in section, ofthe part shown in Fig. 1;

Fig. 3 is a section on the line 33 of Fig.

2 showing the poppet valve actuating mech' anism; I

Fig. 4v is a diagrammatic view of a stoker in which the ram is actuated by a piston in a steam cylinder;

is an enlarged detail showing the cam-operating mechanism. in vertical elevationg V Fig.6 is an end. view partly broken away of the handle control mechanism for the cam; Fig. 7' is a section on the line 77 of 5; and I Fig. 8 is a section on the line 8-S ofFig.

5,looking in the opposite direction from that of Fig.7. l

In accordance with the specific invention herein illustrated, I propose to rotatethe shaft 10 at auniform rate or intermittently as desired, by means 01"- a continuously revolving driving member, connected thereto by a suitable breakable connection, such as a pawl and ratchet device. The parts are so arranged that the connecting member may be permitted to remain in contact with its associated part for an indefinite period or be disconnected from and reconnected thereto by a manually controlled automatically operatedcammechanism. In the construc- I tion illustrated, the power is derived from a continuously rotating worm 12 driven by any suitable means, which in turn rotates a worm gear 13 continuously in one direction.

This worm gearlS is rotatably mounted on the shaft 10 and is arranged to drive the shaft through a ratchet 14: by means of a pawl 15 pivotally mounted on the side of the gear 13. The ratchet member 1 is provided with a single big tooth 1 6 and several small teeth 17 opposite thereto as shown particularly in Figs. 6 and 7.

The-pawl 15 is arranged to be actuated by a set of cams so that it will eitherengage the tooth .16 and rotate the shaft 10 continuously, or it will be caused to engage this tooth only at state-d intervals and permit gear 13 to rotate once, twice or more between successi'v'e rotations ofthe driven shaft 10. To

' shaft 24 and-arrangedto be rotated by the I handle 25 conveniently located on the outside "ofthe casing. It'willbe noted that the shaft is not concentric with the shaft but 1s;

' flocated above it; The ca1n20 is a disc shaped body having avcircular portion 28 which will permit the pawl to contactwith the'ratchet teeth and rotate the shaft 10.; The cam .20

. alsohas cam-surface projections 29, 3 0, 31

and 32 which as will be seen in Fig. 8 have cam surfaces of progressively increasing lei'i'gthand are intended tostop the rotation shaft 10 for definite intervals of time of increasing duration. The cam 21 has a circular outline providing a dwell-portion con centric with shaft 10 except that it is provided with a depression 34 near its bottom.

. A compression spring 35' is arranged to press the pawl inwardly and: hold the cam rider Man; effective raised cam portion or follower l 22,.against the'peripheries of the twocams and 21. By this arrangement I provide lifting portion of variable length,since only th jp rtprojecting above the stiltionalryicam canaifect'the-cam follower. 1 v W] hen the cam 20 is rotated by turning th han dle until the surface 28 :is in .its topprojection 29 is at the top.

. mostposition the projections 29,30, land 32,

will be withdrawn behind'the dwell portion and therewill be no part of cam 20 projecting above thesurface of cam 21 to any 'considerable extent, hence the cam rider 22 will ride around the peripheries of cams 20 and 21 and "permit the pawl 15 to remain in engagement with'the tooth 16 of the ratchet and thus rotate the shaft 10 at a continuous rate.

If new it is desired-to rotate theshaft 10 I through one revolution and then 'holdit stationary while the gear 13 rotates througha revolutiomthe cam member 20 is turned until Then when the cam rider 22 comes around on the surface of 21 and onto the surface of 20an-d' rides up over the projection- 29, it will'lift the pawl 15 from contact with the tooth 16 and thus per- 'mit the ratchet 14 and the shaft 10 to stop rotating. The'cam rider 22 and pawl 15 go around in the direction of the arrows in Figs.

however, is stopped when the ratchet has moved *forward the distance of one tooth, since the slot 34 is of such a length as to lift '77 and 8 until the rider comes to the depression 34 at'the bottom of the cam 21. This occurs when the pawl 15 is opposite'one of the latchet teeth 1'? 1 and the pawl is therefore permitted to engage one of these teeth and start rotating the ratchet 14. This movement,

the pawl from contact with the tooth 17 after it has gone that short distance. Therm after, the ratchet and shaft are left stationary until the cam rider 22 has come to the top andagain mounted the projection 29. This time the projecting cam 29 is found to be so positioned, because of the movement "ahead'of one tooth length, that it will not prevent engagement of the pawl15 with the tooth 16 ,whereupon the ratchet memher and the shaft lO ,will againrotate through a complete turn.

. The lengthsof the cam surfaces on pro 7 jections29, 30, 31 and 32 are suchthattone,

two, three and four revolutions respectively are missediby the ratchet and its shaft before the pawl and'the large tooth comeinto engagement. That is,by turninggtooth 30 to the upperp'osition, thepawl 15' will revolve and move the ratchet member ahead one tooth, then lie-lifted, over thejtooth 16, and again engage a second ratchet tooth and'move it ahead by one tooth distance; Thereafter, when the pawl 15 gets tothe top, the pawl 15 will be permitted to engage the tooth 16 and give it a complete revolution. At the end of eachrevolution of the shaft 10, the cycle will be repeated, moving the ratchet ahead one tooth at'a time. 1 i I If it is desired to stop the shaft '10 while permitting the worm, gear 13to continue rotatin one of these cams. andpr'eferablv'the e V I 1 long cam 32, is moved to such a position that as the device continues its operation the ratchetmember will be moved around until its teeth 1'? are not oppositexthe slot 34 in the outer cam 21. I which has been. lifted from the tooth 16by the cam 82, gets around to the teeth 1?,it cannot engage therewith, because the rider 22 is not opposite the slotted portion and will not let the tooth "16 move inwardly. Therefore the pawl "continues its revolution and is continuouslylifted, over the tooth 16 and is not able to move the' ratchet member 14 forward to get into engagementw ththat tooth.

' Itwill uow 'bc understood that th'isshaft 10 may be utilized to rotate anysuitable mechanism, such as a I'OlJZIIYSWItCh for controlling an electricmotor, or, as illustrated,

a poppet valve mechanism foradmitting steam to an engine cylinder. 1 have ill'us trated in the drawings a simple :type of poppet valve mechanism, although it will he understood that any other form may he used.

Then, :when vthe pawl 15.

As illustrated, thecams 40 and 41'may he keyed" to the shaft 10 and arranged to actu te hlfurcated levers or'rocker arms 42 and 43 which are pivotally mounted independently of each other on shaft 44. They have'r'ollers 45 and 46 on their outer ends in engagement with the cams. Eachlever42 and 48, is arranged to lift the valve actuating stems 47 and 48 at stated intervals. For this purpose, the

vbttumated arms or the e e s-42'and43 ha e pairs of sockets 49' and 50. which support two sets of pins 51 and 52 which carry the cross headshlland 5st to which the valve actuating It will be obvious that various changes may i be made inthis construction within the scope of my invention and the claims are to beinterpreted accordingly. I

Having thus described my invention, wh at I claim asnew and desire to secure by Letters Patent is: V p 1'. A driving mechanism comprising a continuously rotatable driving shaft,a rotary driven member, a pawl fastened to one member and-acooperatingratchet connected to theother, and manually adjustable cam device including relatively adjustable cams and a cam follower connected with said pawl.

,s'aidcams being so constructed that they may 'ither provide a dwell throughout the. entire cam surface and "-thus cause the pawl to remain'fin engagement with the ratchet for an indefinite period or theymay provide a follower lifting portion extending above the dwell and thus remove the pawl from engagement with the ratchet at stated intervals, whereby the driven shaft may be rotated continuously or intermittently for a predetermined period of time. s

2. A driving mechanism comprising driving and driven members, a ratchetconnected to one member and a pawl to the other, a cam follower connected with the pawl and arranged to make and break the connection between said pawl and ratchet, and a stationary I cam having a dwell portion and movable a follower. lifting portion mov-' cam having able to an ineffective position behind the dwell portion or to an effective follower lifting position, whereby a peripheral cam surface is provided of such character that the cam follower may ride continuously therearound and cause the pawl to remain in contact with the ratchet, or the pawl will be periodically removed from contact with the ratchet and the driven member will remain substantially stationary while the driving member rotates through a complete revolution. V

3. A driving mechanism comprising rotary driving and driven members, a ratchet having a large tooth and a small tooth which is connected to one member, a pawl connected to the other and arranged to drive the ratchet,

a cam follower connected to the pawhnnd a cam device having a raised portion Larranged to lift the-pawl from contact with 1: large tooth and adepression permitting con tact with the small tooth, said parts bci so constructed and crrangei that the paw will contact with the lnr e tooth and rotate the driven member throur substantially one revolution and then be lifted from contact therewith by the/follower passing over the raised cam portion, and thereafter asthc driving member 'otates the pawl. will be permitted by'said depression to contact with the small tooth. for a short time and more the ratchetforward a suliicient distance to prg mit engagement of the pawl with the large tooth again, whereby the driven member is rotated intermittently.

4. A drivingmechanism comprising a continuously rotated driving member, a driven member, a pawl connected to one and a ratchet tothe other, said ratchet having a large tooth and several small teeth, a cam follower connected to the pawl, a movablecam having raised port-ions of difierent lengths capable of lifting the pawl from the large tooth as the follower rides thereover, a cam having a depressed portion in the path of the follower capable of permitting contactof the pawl with a small. tootlnand means to ad just the cams so that the pawl will be removed periodically from engagement with the large tooth, said parts being so constructed and arranged that the pawl may re volve the large tooth through a single turn and then be removed therefrom, after which the pawl engages a small tooth and moves the ratchet forward a short distance, the lengths of the raised cam portions being such that the pawl may be held from engagement with the large tooth while the driving member rotates through one or more rotations.

5. A driving mechanism comprising a continuously rotatable driver, a driven member, a pawl and ratchet connection therebetween, a cam follower arranged to make and break said connection, a cam having a substantially circular outline concentric with the ratchet arranged to cause the pawl to revolve continuously in contact with the ratchet, a movable cam having an effective raised portion thereon, and means to move said movable cam to interpose said portion in the path of the cam follower to break the driving connection periodically or to withdraw it behind the other cam, whereby the driven member may remain still for an indefinite time or be rotated a single turn and then caused to stand substantially still while the'oriver makes a predetermined number of turns.

6. A driving mechanism comprising a continuously rotated driving member, a driven member, a ratchet having a large tooth and several small teeth connected with one of said members, a pawl operatively associated with the ratchet andconnected with the other of said members, and a cam device having a cam follower'connected'with said pawl and two relatively movable cam members, one

having a substantially circular outline concentric with the ratchet and'a depression therein, and the other cam having projections of different lengths arranged to be interposed -in the path of the cam fol-lower above the circular cam to remove the pawl from contact 'with the big tooth, and the depression in the cam being solocatedthat the pawlmay engageone ofthesmall teeth and move it through a short distance and thereby'move.

the ratchet ahead until the-pawl will not be prevented from contactingwith' the large I tooth, whereby the driven member maybe 1 0- tated throughout a complete revolution and then permitted to remain substantially stationary while the driving member rotates one or morerevolutions.

7, A driving mechanism comprising a jdriv= er, a driven member, a; pawl and ratchet connection therebetween, a cam follower arranged to connect and disconnect the pawl from the ratchet,a cam to control said cam follower comprising two relatively adjustable'parts, I

one 'servingto provide a dwell portion and i the otherhaving follower lifting portions of differentlengths capable ofholding the fol- 1 lower lifted for different time intervals, said SL-A driving mechanism comprising a rotatab'le drivin member,-.a dr1ven member, a

follower lifting portions being movable suc- -cessively' from an ineffective position behind the dwell portion to an effective follower lifting position, and means for moving the cam andcam follower relatively so that the pawl tive length of the follower lifting portion.

releasable driving connection therebetween, meanscompr smg a cam follower to release or makesaid driving connection, and a cam arrangedto contact with the cam follower,

said cam being constructed of two relatively adjustable parts, onehaving a dwell portion,

allel thereto so as tov vary the effective shape of the cam surface. i

10. A driving mechanism comprising a continuously rotatable driving member, a driven member, a releasable driving connec tion therebetween, a-cam follower arranged to release or make said Idriving connection and rotatable with the driving member, and a cam arranged tocontact with the cam follower, said cam being constructed of two parts, one of which is stationaryfand the other of which is manually adjustable rotatably, during the operationof themechanism, about an axisspaced from the axis of the driving member and parallel thereto so as'to vary the effective shape of the cam surface.

a 11:; A" driving mechanism comprising a ro-' tatable driving member a rotary driven member, areleasable revolving pawl on one member and ratchet teeth on the other, a cam follower connected with the pawl to lift it froincontact with the teeth anda cam arranged to control and operate the revolving follower, said cam being madeof two relatively adjustable parts, one having a dwell portion and the other having a follower lifting portion movable toan inefiective position behind the dwell portion or to an effective follower lifting position, whereby the, efiec tive shape of the cam. may be varied to cause 9 the pawl to remain in contact withthe teeth or to provide a projection: on thecam sufliciently high to lift the pawl periodically out of 'contactwith theratchet teeth. 7 p Signed at Worcester, Massachusetts, this 12th day of Sept.,1924.

and the other having a follower lifting portion movable to an ineffective position behind the dwell portion or to an effective follower lifting position. V

9. A. driving mechanism comprising a continuously rotatable driving member, adriven member, a releasable drivingv connection therebetween, a cam follower arranged to re lease or" make said driving connection and rotatable, withthe driving member, and a cam arranged to contact with the cam follower, said cam being constructed of two parts, one of whichis adjustable rota-tably relative to the other about an-aXis spaced from the axis of the driving member and par- DALLAS r, entr -mun,

CERTIFICATE OF CORRECTION.

Patent No. 1,787,265. Granted December 30, 1930, to

DALLAS F. GRAHAME'.

It is hereby certified that the name of the assignee in the above numbered patent was erroneously described and specified as Sanford Riley Stoker Corporation", whereas said name should have been described and specified as Riley Stoker Corporation, as shown by the records of assignments in this office; and that the said Letters Patent should he read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of May, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

